Trimming mechanism for sewing-machines



R. R. HUGHES, JR. TRJMMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED SEPT. 2, I916.

Patented Dec 28,, 1920.

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R. BL HUGHES, JR. TRIMMING MECHANISM FOR SEWING MACHINES. APPLICATION FILED SEPT. 2. I916.

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R. R. HUGHES, JR. TRIMMING MECHANISM FOR SEWING MACHINES..

APPLICATION FILED SEPT. 2, 1916.

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APPLICATION FILED SEPT. 2, I9I6.

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ROBERT E. HUGHES, JR, 015 UTICA, NEXV YORK, ASSIGNOR'TO UNION SPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TRIMMING MECHANISM FOR SEl/VINGr-MACHINES.

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T 0 all whom it may concern:

Be it known that 1, ROBERT E. HUGHES, Jr., a citizen of the United States, residing at Utica, in the county of Oneida, State of New York, have invented certain new and useful Improvements in Trimming Mechanisms for Sewing-Machines, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

The invention relates to new and useful improvements in trimming mechanisms for sewing machines, and more particularly to a trimming mechanism which may be rendered efiective or inefl'ective at the will of the operator during the running of the machine.

An object of the invention is to provide a trimming mechanism of the above character wherein the movable trimming blade is pivoted and swings about its pivotal center for its cutting operation, and wherein the working position of said trimming blade may be shifted so that said blade will either cooperate with the stationary trimming blade and cut the material being stitched, or its position will be wholly at one side of the cutting edge of the stationary blade so that it will be ineffective to cut the material.

A further object of the invention is to provide a trimming mechanism of the above character wherein the support for the movable trimming blade is located beneath the Work support and said blade projects above the said work support only when performing its fabric cutting action.

A still further object of the invention is to provide a trimming mechanism of the above character wherein the movable trimming blade is pivoted beneath the work support, and projects above, forward of the needles, and overhangs the work support, the cutting edge of said movable blade being on the under part of the overhanging blade, while the upper edge of said blade is smooth and rounded so that the two superposed fabrics may be separated and the lower layer only cut.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed In the drawings which show by way of illustration one embodiment of the invention:

Figure 1 is a view partly in section and Specification of Letters Patent. Pabgntgfl Bea 28, 1920 Application filed. September 2, 1916.

Serial No. 118,193.

tion of the movable trimming blade when r the parts are connected as shown in Fig. 3;

Fig. 5 is a view similar to Fig. 3, but showing the operating parts shifted for rendering the movable blade ineffective;

Fig. 6 is a View similar to Fig. 4:, but showing the working position of the blade with the parts connected as shown in Fig. 5;

Fig. 7 is a plan view of a portion of a work support showing the throat plate, the feed dog, the trimming blades and the strip deflector Fig. 8 is a view showing more or less diagrammatically the trimming blade cutting the lower layer of fabric, the trimmed off edge being deflected away from the material and the upper layer of fabric stitched to the cut edge passing between the needles;

Fig. 9 is a view showing more or less trimming mechanism for a sewing machine,

which trimming mechanism includes a stationary blade mounted so that its cutting edge is substantially flush with the upper face of the work support and a movable trimming blade which is pivoted at a point beneath the work support and oscillates about said pivot for cutting the fabric.

The movable trimming blade is carried by a shaft located beneath the work support position of the movable trimming blade;

Said blade oscillates and overhangs the Work support when raised and in its normal work'- 7 cutting position. When, however, said blade is shifted to ineffective position then it is wholly beneath the upper surface of the work support, and its cutting edge is out of range of the stationary trimming blade.

Referring more in detail to the drawings, the invention is shown as applied to a sewing machine having a supporting bed 1, which carries a work support 2, and an overhanging arm 3. A needle bar 4 reciprocates in the outer end of the overhanging arm, and

said needle bar as herein shown carries two needles 5 and 6. The needle bar is reciprocated by a needle lever 7 which is connected to the needle bar by a link 8 and the needle bar is oscillated by an eccentric strap 9, which cooperates with an eccentric on the main shaft 10.

The material is held on the work support 2 by a presser foot 11. The presser foot is carried by a presser bar 12, mounted in the overhanging arm of the machine. Cooperating with the presser bar beneath the work support is a feed dog 13. This feed dog is carried by a feed bar 14 which is pivoted at 15 to a feed rocker 16. The feed rocker is pivoted to the bed plate 1 at 17. This feed rocker is oscillated by any suitable mechanism which in turn moves the feed bar back andforth. The feed bar is raised and lowered by an eccentric 18 mounted on the main shaft 10.

Located in front of the stitching mechanism are the trimming blades. The blade 19 is the fixed blade. This fixed trimming blade 19 is mounted in a suitable groove in the throat plate 20 of the machine and is held therein by a screw 21. Said blade projects rearwardly to a point close to the needles. The position of the needles is indicated by the needle openings 22 and 23. See Fig. 7.

The opening 22 receives the needle 5, while the opening 23 receives the needle 6. Cooperating with this fixed blade 19 is the movable blade 24 of the trimming mechanism. Said movable blade is secured at the end of a shaft 25. (See Fig. 1.) The shaft 25 is mounted to oscillate in bearings 26 and 27 carried by the under face of the work support 2. Said blade is fixed rigidly to the shaft and is constructed with an overhanging portion 28 which is formed at its lower face with a cutting edge 29. The upper edge 30 of this movable blade 24 isrounded off as shown in Fig. 14. The rounded off portion merges with the cutting edge at the point 31. The shaft 25 is moved endwise in its bearings by a spring 32 which surrounds the shaft and bears at one end against a supporting ledge formed in the work support, and its other end against a collar 38, which is fixed to the shaft 25 by a set-screw 85, this spring serving to hold the movable blade against the ledger blade.

On the other end of the shaft 25, there is an arm 36.. This arm is formed with a slot 37, and the arm is secured to the shaft 25 by a set-screw 38. A lever 39 is pivoted at 40 in a bearing on the work support 2. This lever has a forked end 41 which cooperates with a cam 42 mounted on the main shaft 10. The upper end of the lever 39 is formed with a slot 43. A link 44 extends through this slot. A cross pin 45 is carried by the lever 39 and extends across the slot. The link 44 is provided with two notches 46 and 47, (see Figs. 3 and 5), which notches are adapted to separately engage the cross pin. A leaf spring 48, bearing against the end of this link 44, yieldingly forces the same upwardly so as to cause one of its notches to engage this cross pin. The other end of the link 44 is connected to a pivot-pin 49 which is adjustable in the slot 37 and is held in an adjusted position by a clamping nut 50.

' From the above description, it will be apparent that as themain shaft 10 rotates, the lever 39 will be oscillated and this will move the link 44 endwise and in turn impart an oscillation to the shaft 25, carrying the movable trimming blade. When the notch 46 engages the cross pin 45, the trimming blade will oscillate from the full line position, shown in F ,ig. 4, back and forth to the dotted line position, shown in this figure. When in the full line position, the blade is raised above the upper surface of the work support. The layer of fabric which is severed is carried by the feed of the machine underneath this raised blade. After the feed has taken place, then the cam 42 will move this blade 24 to the dotted line position shown in Fig. 4 and this severe the fabric underneath the blade. It is then again raised and the fabric moved forward underneath the blade.

This machine is especially designed for severing one of two superposed layers of fabric. The blade as above noted, has an upper rounded face and a penetrating point. The penetrating point will enter the folded edge of the fabric when pressed against the same, and the blade will enter between the two layers of fabric, lifting the upper layer F on its rounded face, while the lower layer F passes underneath the overhanging cutting edge of said blade and is cut as above described.

The presser foot has a recess 51 on its underface for receiving the blade 24 during its upstroke and this presser foot extends forwardly over the movable trimming blade and serves to hold the layers of fabric down on the work support around said blade.

As clearly shown in Fig. 7 of the drawings the movable blade 24 is located directly .in front of the two needles 5 and 6. The

cutting face of the blade 24 is on the left as viewed in this figure, and is in a line passing between the needles and close to the needle 5. Directly in rear of the movable blade 24 is a strip deflector D. The purpose of this deflector is to take the trimmed off edge and carry it out of the path of both the needles so it will not be stitched, while the other edge passes straight back between the two needles. Coeperating with the two needles beneath the work support is a threaded looper 53 which enters both needle thread loops, and the looper thread connecting the needle thread loops will cover and tie down the cut edge passing between the needles.

The looper 53 is carried by a looper carrier 54 which is pivoted at 55 on a looper support 56. The looper carrier is oscillated by a link 57 which is connected to the needle lever extension 58.

The above operation takes place when the link 44 has its notch 46 engaging the cross pin 45. The operator by pressing down on the link 44, may disconnect this notch 46 from said cross pin and move the link 44 so as to cause the notch 47 to engage the cross pin. This may be done while the machine is in operation. When the notch 47 is brought into engagement with the cross pin, the link 44 has been moved endwise toward the front of the machine and this will swing the arm 36 and shift the shaft 25 so as to change the working position of the movable trimming blade 24, and said blade will now oscillate from the full line position shown in Fig. 6 to the dotted line position shown in this figure.

It will be noted that even when said movable blade is in its extreme upper position with the parts arranged as above stated, said upper blade is not raised above the plane of the work support, and is, therefore, out of range of the cutting edge of the stationary cutting blade and is ineffective. In other words, when the link 44 is positioned as shown in Fig. 3, the trimming blade is in effective working position and will operate to cut the layer of material passing underneath the blade. When, however, the link is shifted, and the parts are positioned as shown in Fig. 5, then the cutting blade is in ineffective working position, and will not operate to cut the material.

The cutting blade is brought back again to cutting position by shifting the link 44 to cause the notch 46 to engage the cross pin. This shifting of the link raises the cutting blade, and if a layer of material is over the cutting blade, it will be raised into the recess in the underface of the presser foot and the presser foot forces the fabric down into the cutting blade and will cause the fabric to be penetrated by the piercing point of the blade and said blade will then enter between the layers of fabric and begin its cutting action.

It is obvious that minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit of the invenion as set forth in the appended claims.

Having thus described my invention,what I claim as new and desire to secure by Letters Patent is 1. A trimming mechanism including in combination, a work support, a stationary trimming blade carried by the work support and having its cutting face substantially flush with said work support, a shaft located beneath the work support, a movable trimming blade mounted directly upon said shaft and turning about the axis of said shaft as a center, said blade being disposed so as to project forwardly from said shaft and adapted to project through and overhang the work support, means for oscillating the shaft, and means for varying the oscillating position of the shaft whereby the throw of the movable blade may be wholly beneath the work support and the trimming mechanism thereby rendered ineffective at the will of the operator.

2. A trimming mechanism including in combination, a work support, a stationary trimming blade carried by the work support and having its cutting face substantially flush with said work support, a shaft located beneath the work support, a trimming blade mounted directly upon said shaft and turning about the axis of said shaft as a center, said blade being disposed so as to project forwardly from said shaft and adapted to project through and overhang the work support, an arm attached to said shaft, a main shaft, a lever oscillated by said main shaft, a link connecting said arm to said lever, and means whereby the connection between the link and the lever may be varied for shift ing the working position of the movable trimming blade, whereby the trimming blade may be positioned wholly beneath the work support and rendered ineffective.

In testimony whereof, I affix my signature, in the presence of two witnesses.

ROBERT E. HUGHES, JR.

' Witnesses:

EARL C. CLARK, ARTHUR L. WILCOX. 

